Derivative of xlnx = 1?

Hi there,

Answer book says xlnx differentiates to 1 + lnx - how did they get to this? I got y= xlnx so dy/dx = x/x = 1

let u = lnx differentiates to 1/x
let v = x differentiates to 1

d(uv)/dx = (du/dx)*v + (dv/dx)*u (product rule)
= x/x + lnx = 1 + lnx

Retropmot

let u = lnx differentiates to 1/x
let v = x differentiates to 1

d(uv)/dx = (du/dx)*v + (dv/dx)*u (chain rule)
= x/x + lnx = 1 + lnx

Product rule, you mean. :p:

Craver

Hi there,

Answer book says xlnx differentiates to 1 + lnx - how did they get to this? I got y= xlnx so dy/dx = x/x = 1

It couldnt possible = 1 since the integral of 1 with respext to x is x+c, which =/=xlnx

As above, product rule

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